time: ensure that offload mode switches parent out of ramp

time: ensure that offload mode switches parent out of ramp

If we have worker threads submitting IO for the jobs AND using
ramp time, then we need to ensure that the parent job is switched out of
ramp mode. This normally happens as part of IO submission, but since
we have worker threads doing that for us, it never happens for the
parent.

Fixes: https://github.com/axboe/fio/issues/459
Signed-off-by: Jens Axboe <axboe@kernel.dk>